1. Field of the Invention
This invention relates to a spacer interposed between two members, and more particularly to a spacer interposed between a caliper and a steeling knuckle of a disk brake for vehicles.
2. Description of the Related Art
Disk brakes are known as a brake system of vehicles or the like. For example, JP-A-9-303440 discloses one of conventional disk brakes. FIG. 18 illustrates one of the conventional disk brakes and FIG. 19 illustrates a spacer used in the disk brake. The shown disk brake comprises a caliper 1 accommodating brake pads and a brake disk 9 against which the brake pads are pressed at opposed sides so as to slidingly hold the disk therebetween, whereby a braking force is effected. The caliper 1 has a mounting bore and a steeling knuckle 4 provided at the vehicle side also has a mounting bore co-axial with the bore of the caliper. A bolt 3 is screwed into the mounting bores of the caliper 1 and steeling knuckle 4 so that the caliper is mounted on the steeling knuckle. Either one of the caliper 1 and the steeling knuckle 4 is made of a metallic material, whereas the other is made of an aluminum material. Accordingly, connected portions of the caliper 1 and steeling knuckle 4 are corroded by the electrochemical reaction. For the purpose of preventing the corrosion, a spacer 5 serving as an electrolytic corrosion preventing member is interposed between the caliper 1 and the steeling knuckle 4.
The spacer 5 comprises a generally ring-shaped body 6 having two claws 7 and a temporarily retaining portion 8 formed on a outer peripheral edge of the body. The caliper 1 includes amounting portion 10 to which the body 6 of the spacer 5 is mounted. The mounting portion 10 is held between the claws 7, and a distal end of the temporarily retaining portion 8 is caught on an engagement face 2 of the caliper 1 so that the caliper is held between the body 6 and the temporarily retaining portion, whereby the spacer is temporarily retained on the caliper. Subsequently, the bolt 3 is inserted into the mounting holes of the caliper 1 and steeling knuckle 4 and tightened up so that the caliper and the steeling knuckle are tightened against the spacer.
In the above-described spacer 5, however, the claw 7 and temporarily retaining portion 8 are exposed outside. Accordingly, foreign matter tends to be brought into contact with the claw 7 and the temporarily retaining portion 8 when the spacer 5 is temporarily retained on the caliper 1. As a result, the foreign matter sometimes releases the spacer 5 from the temporarily retained state or deforms the claw 7 and the temporarily retaining portion 8.
Furthermore, the claw 7 and the temporarily retaining portion 8 are formed on the outer peripheral edge of the body 6. This renders a developed form of the spacer 5 large and accordingly reduces the material yield.
Additionally, in order that the spacer 5 may be mounted to the caliper 5, the body 6 of the spacer 5 is placed opposite the mounting portion 10 of the caliper 1. In this state, the claw 7 is caused to engage the mounting portion 10 while the body 6 is pulled downward so that the temporarily retaining portion 8 is kept opened. Subsequently, the temporarily retaining portion 8 is pressed against the surface of the caliper 1 so as to be engaged with the engagement face 2. Thus, the mounting work is troublesome. Accordingly, the mounting of the spacer 5 cannot easily be automatized.